The match today will come down to how well Zverev is serving. He's lost his serve 7 times in his last three matches vs three unseeded players, compared with Tsitsipas who has the most efficient non-servebot hold game on clay this year and has been broken 4 times over the same period, vs the #31, #12 and #2 seeds. Add to the equation Tsitsipas' improved return numbers across the board (about 41.5% points won on clay this year, pre-RG it sat at about 37% vs top 10 but winning 40% of points on Medvedev's serve will have boosted that), and a strong serving performance from Sascha becomes even more essential if he wants to stand a chance.